System and Method for Digitally Signing Documents Using Biometric Data in a Blockchain or Pki

1. A method executed in servers that interface with a Database Management System (DBMS) for signing and exchanging documents electronically, said documents being signed using biometric information of subscribers that sign the documents, the method comprising the steps of: a. capturing biometric data blocks associated with a subscriber; b. generating a biometric key, at a subscriber node, comprising a biometric hash derived deterministically from biometric feature elements of the biometric data blocks by a quantization that constructs intervals for each of the biometric feature elements, where the biometric hash is generated by mapping the biometric feature elements into the intervals; c. sending the biometric hash to a plurality of observer nodes; d. receiving a plurality of responses from the plurality of observer nodes; each received response validating or invalidating the biometric hash based on a biometric hash ledger associated with the subscriber at each one of the plurality of the observer nodes; e. authenticating the subscriber based on responses that validate the biometric hash; f. sending the biometric hash to the plurality of observer nodes to update all biometric hash ledgers associated with the subscriber based on a time stamp sent from the subscriber node; and g. allowing the subscriber to sign a document if the subscriber is authenticated and if an entered PIN verifies an identity of the subscriber.

2. The method of claim 1 further including the step of executing a plurality of flow engines at each node used by the subscribers and observers, including a first flow engine for forwarding the biometric key of the subscriber and a plurality of second flow engines for forwarding biometric keys derived from biometric data associated with observers and exchanging biometric keys between the subscriber node and the plurality of the observer nodes.

3. The method of claim 1 further including the step of the flow engines comprise workflow engines that allocate tasks to the subscribers.

4. The method of claim 1 further including receiving a private biometric key from a card reader, wherein the private biometric key is derived from the subscriber's biometric data, wherein the subscriber is further authenticated based on a certificate that includes a public key derived from the private biometric key before the subscriber is allowed to sign the document.

5. The method of claim 1 further including using the biometric hash in a block of a blockchain associated with the subscriber, wherein the biometric hash is stored on a plurality of nodes, and authenticating the subscriber using a symmetric cryptography method that is based on using the biometric hash as a shared secrete in the symmetric cryptography method.

6. The method of claim 1 further including using the biometric hash in a block of a blockchain associated with the subscriber, wherein the biometric hash is stored on a plurality of nodes, and authenticating the subscriber using asymmetric cryptography that is based on using the biometric hash as a private key and a certificate that includes a public key derived from the biometric hash.